Teleprinter apparatus with electronic speed control

ABSTRACT

A teleprinter system provided with a variable speed control for different transmission rates. Rather than attempting to vary the speed of a motor or mechanical transmission, the speeds of those devices are maintained constant and the rate is controlled by varying the speed of keying of the bits being transmitted and received.

United States Patent 1151 3,643,022

Ferroglio 1 1 Feb. 15, 1972 [54] TELEPRINTER APPARATUS WITH 3,457,3687/1969 Houcke ..l78/l7 ELECTRONIC SPEED CONTROL 3,419,678 12/1968 Ariel..l78/23 3,296,370 l/l967 Clark... ..l78/17 [721 lnvemo" 4 3599 E P95.i9TqriP; ?!Y 2,916,727 12/1959 Jones ...340/172 5 I or & C" T 3,059,04810/1962 Lamin etal........ ..l78/3 [73] 'Ass'gnee JEN-194W 3,012,09612/1961 Steinmetz etal.. .178/17 22 Filed! Apr. 18, 1969 3,011,02211/1961 Gaffney m1. l78/53.I 2,945,092 7/1960- Gardberg ..17s/53.1 [21]8171327 2,712,037 6/1955 Phelps 6131 ..l78/l7 [30] Foreign Application Pio it D t Primary Examiner-Kathleen H. Claffy Assistant Examiner-TomDAmico Apr. 18, 1968 Italy ..5l325 8/68 Atmmey Bh-ch, Swindler McKie &BeCFk-en [52] U.S.Cl. ..l78/l7R 57 1 ABSTRACT 51 1111.0. ..1104113/14 I[58] Field 61 Search ..-178/2, 3, 17, 53, 53.1, 4.1, A telePnmer SystemPmvlded with a P control 178/23 179/2 DP 3 340/1725 for differenttransmission rates. Rather than attempting to vary the speed of a motoror mechanical transmission, the

I speeds of those devices are maintained constant and the rate is l [56]Reierences Cltgd controlled by varying the speed of keying of the bitsbeing UNITED STATES PATENTS transmitted and received.

3,558,821 1/1971 Lutz ..l78/17.5 3 Claims, 3 Drawing Figures t AVLAstiEEiou QVL' swnw a be d e V NETWORK NETWORK 4 D51 {F 2 1 llll l fll I1 1 1 l 1 FREQUENCY DECODING DIVIDER DSP CIRCUIT I OSCILLATORTRANSMISSION UNIT I TRANSMISSION PATENTEDFEB 15 1912 3,643,022

SHEET 1 OF 3 AVLA SPEED 4 SELECTION VL swmn a bc :1 e as 4"! N"! VSELECTION E SELECTION 53 NETWORK NETWORK DST {F 24 WHHHA H l 1 l 1 L l 1FREQUENCY oacoome DIVIDER 'f CIRCUIT I i OSCILLATOR COUNTER H T VL VT vD$T *Q-NKEYBOARN 4 M I g 15g USN LA VT DST i1 VL PUNCHED MI 16 i TAPEREADER a 11 .SLA AVLA 1 D ,RA VT l a VR REPLY a1 DEV-ICE 3 12 VL 1 TREGISTER A TRANSMISSION UNIT I TRANSWSSION L LINE Fig. 1

mvsmon LUIGINO FERROGLIO PAIENTEDFEB 15 me sum 2 UF 3 S l E N G A W 5 In1, 00 q 1 W ID (0 IO ID IO 77 m C R u 5 E 6 u M W M M 00K N 0 mm rr 5 5Q :4 I. N 4 y I v h "K W M Eli T0 ED EMH CW A UI Puuw. E QV S E .LH C 9REGISTER Fig.2-

mama DEVICE MOTOR RECEIVING UNIT INVENT LUIGIN 0 FERQ SCL I0 PATENTEDFEB15 m2 3.643.022

SHEET3UF3 D 100 D5 D6 1 D4 8 :DSP: DST. D1 02 DIS AVLA

D50 D? D8 ZDSP DST DI DIS Q F1 AVLA Fig.3

INVENTQR. LUIGINO FER OGLIO TELEPRINTER APPARATUS WITH ELECTRONIC SPEEDI CONTROL GENERAL DESCRIPTION The present invention relates to ateleprinter. Known teleprinters usually consist of two distinct parts: atransmission unit and a receiving unit.

The transmission unit consists of an input keyboard, control device andserialization device for passing the data fed into the keyboard to thetransmission line in a serially coded form, each item being preceded bya start bit and followed by a stop bit, in accordance with thetelegraphic transmission procedure of the asynchronous type.

The receiving unit consists of a distributor (parallelizing device) forthe serially coded data received from the transmission line, a controldevice, and a printout device by which the data received is reproduced.

The upper limit of telegraphic speed, i.e., of the number of telegraphicimpulses that can be transmitted or received per unit of time, isdetermined by the transmission line. In known teleprinters, thetelegraphic speed, below the limit determined by the line, is varied bymeans of a gear change on the motor shaft. The fact is that thetelegraphic speed in the case of a teleprinter cannot be varied byacting directly on the motor of the machine, since it is not possible tomodify the speed of the motor with the required degree of accuracy. Itis therefore only by acting on the mechanical gearing which transmitsthe movement of the motor shaft of the machine to the devices whicheffect all the established functions that the speed with which thesefunctions can be actuated, i.e., the telegraphic speed, can be variedaccurately. The operation of varying the gearing has the effect ofvarying the load on the motor of the machine, so that the ballastresistance of the motor has to be regulated. This method of modifyingthe telegraphic speed in known teleprinters further entails fatigue andconsequent wear of the mechanical components, since they are forced tooperate at speeds different from that for which they are dimensioned.Furthermore, the presence of the gear change and of the set of ballastresistances has the effect, in the known apparatus, of considerablyincreasing the cost incurred and the space occupied.

The object of this invention is to overcome such drawbacks.

According to the invention there is provided teleprinter apparatuscomprising a transmission or receiving unit which includes a registerand a timing device which emits timing pulses which time the serialreadout to line of the bits of a character entered in the register froman input device, or which time the shifting into the register of bitsreceived from line for transfer of a character to an output device, thetiming device comprising an oscillator feeding a frequency divider and amanually operable selection network for selecting outputs at differentfrequencies from the divider to constitute the said timing pulses.

DETAILED DESCRIPTION The invention will be described in more detail,with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of the transmission unit of apparatusembodying the invention;

FIG. 2 is a block diagram of the receiving unit of the apparatus; and

FIG. 3 shows diagrams relating to the control of the stepbystep reader,for telegraphic speeds of 50 baud and 100 bauds.

DESCRIPTION OF TRANSMISSION UNIT Referring to FIGS. 1 and 2, theteleprinter embodying the invention consists of a transmission unit anda receiving unit. The transmission unit inFIG. 1 comprises, by way ofinput devices, a keyboard TA, a punched tape reader LA, and an automaticreply device RA which conveys the address of the unit at the request ofthe correspondent or when called for by means of the keyboard.

The keyboard TA is a normal keyboard, similar to that of a typewriter,with the addition of keys for the issuance of service codes and keys forspecial functions, and in which a certain configuration of code barscorresponds to each key. In particular, the code keyboard may be of thetype described in the specification of our US. Pat. No. 3,306,4l7. Thecode bars provided act on microswitches which supply electrical signalscorresponding to the said bars, and another microswitch is actuatedsimultaneously with a key and supplies a control signal VT indicatingthat the transmitting unit is being used by the keyboard.

The machine is also provided with a starting key for the punched tapereader LA. The tape' reader can be of the type described in thespecification of our U.S. Pat. application Ser. No. 793,830. Thestarting key of the reader LA actuates a microswitch which supplies acontrol signal VL indicating that the transmitting unit is beingutilized by the tape reader.

Finally, the automatic reply device RA is started by a key provided inthe machine or by a signal emanating from the receiving unit. Thestarting key causes a microswitch to produce a control signal VR showingthat the transmission unit is being utilized by the automatic replydevice RA. Alternatively, the control signal is supplied directly by thesignal emanating from the receiving unit if it is by this latter thatthe automatic reply device is started up. The'automatic reply device RAcan consist, e.g., as described in the specification of US. Pat.application Ser. No. 714,488 assigned to the assignee of this invention,of a drum to the periphery of which are connected shaped strips, eachrepresenting 'a certain combination of codes. The drum rotates by onestep'at a time, presenting the shaped strips to feelers. These latteract on eight microswitches, which provide the electrical signalscorresponding to the eight code bitspresented on the scanned strip andrepresenting one single character.

The keyboard TA, the punch-tape reader LA, and the automatic replydevice RA, by paths 1, 2, and 3, respectively, give access to a registerM, of a type already known in itself and consisting of eight bistableflip-flops Ml M8, in which can be stored the eight signals generated bythe eight microswitches, for which one of the aforementioned paths 1, 2,and 3, respectively, is open. Thus path 1 is opened by signals which arethe complements of the control signal VL emanating from the tape readerLA and the control signal VR emanating from automatic reply device RA,both acting on a gate 10. In other words, the data keyed in will onlyenter the register M provided that no item is coming at the same timefrom the tape reader of the automatic reply device.

Similarly, path 2, for the data emanating from the tape reader LA, isopened by the complemented signals VT and VR emanating respectively fromthe keyboard TA and from the automatic reply device RA and applied to agate 11. Finally, the path 3, for the data emanating from the automaticreply device RA, is opened by the complemented signals VT and VLemanating respectively from the keyboard TA and from the tape reader LAand applied to a gate 12.

To sum up, when one of the three paths 1, 2 and 3 is opened, the othertwo are closed. At the same time, each control signal VT, VL and VRenables a timing device via a gate 13. The purpose of this latter is tosupply the intervals of the individual bits of the characters emergingfrom the register M and directed to the transmission line L.

The length of the bit intervals is fixed by the operator of the machine,who by means of a speed selection switch 22 acts directly on electronictime bases, while the mechanical units of the machine always function atthe same speed. The timing device gives a signal K which causes to beread into the register M the alpha-numerical character or codeexpressing a function, emanating from the keyboard or from the reader orfrom the automatic reply device, according to whether path 1, 2, or 3 isopen. Let us suppose that a character has been selected on the keyboardTA: the open, gate 10 will then be open, while gates l l and 12 are atthe same time blocked. The timing device has been started up on theswitching-on of the machine, so that after the receipt of the signal VT,i.e., after the latter has enabled the gate 13, it supplies theintervals of the bits of the character to be transmitted, of the lengthselected by the operator, acting on the telegraphic speed selectionswitch 22. In particular, let us suppose that the character emanatingfrom the keyboard is coded in 7 significant bits plus one control bit:the timing device will then supply the eight intervals D1 D8 of theeight bits of the character. As the transmission is asynchronous, astart bit and a stop bit are necessary before and after the character,respectively, and the timing device then also supplies the interval ofthe DST start bit and the interval of the DSP stop bit, which godirectly into the line L.

After the interval of the DST start bit, the timing device supplies theright intervals D1 D8, applied to gates 14 21, respectively, at theoutput of the eight flip-flops Ml M8, respectively, which constitute theregister M. Then, in a sequence determined by the signals D1 D8generated by the timing device, the bits of the stored character passinto the line from the register M. After the interval of time D8, thetiming device, as mentioned, supplies the interval DSP directly to theline L, so that in the line a signal level is present which representsthe stop for the interval of a bit and which remains such until thesucceeding start signal DST, even if the timing device, after theinterval DSP, is blocked, owing to the extinction of the VT signal whichactuates the gate 13, as a result of the said DSP signal. Subsequently,when a further character is keyed in, the aforementioned process isrepeated, i.e., the character from the keyboard passes to the registerM, and from there, with the delay produced by the timing device, it isshifted into the line.

In the same manner, the transmission of the characters is effected fromthe tape reader LA and from the automatic reply device RA. Inparticular, the tape reader, similar to that described in thespecification of the aforementioned application Ser. No. 793,830, is astep-by-step reader. In this case, the reader, as already mentioned, isstarted up by a command present in the machine, SLA, which supplies thesignal VL. This signal prevails until the reader is blocked by anotherkey present in the machine.

Owing to the continuous presence of the VL signal the timing device isstill in operation, continuously forming time intervals corresponding tothe start, to the eight character bits and to the stop, then again tothe start, to the eight bits and to the stop, and so forth. Thus thecharacters read by the tape reader must be present in the M-register ateach start, i.e., the M-register must be refilled at each start. On theother hand, the reader, being a step-by-step reader, operatingcontinuously from character to character, must receive the commandsignal for reading and simultaneous feed. The time cycle ofthe tapereader itself fixes the interval of time between the energization of thereading command electromagnet and the moment when the character read isactually available to the output microswitches of the reader, and, alsoas described in the above-mentioned specification, the character onlyremains available for a very short period. Consequently, the moment forthe energization of the electromagnet for the reading command isgoverned by the decoding operated by the timing device for the bitintervals, and the fact is that if, within a DST interval, the characterread by the tape reader is to be available in the register M, the samereader must be energized in advance by a definite selected interval oftime.

This command for the energization of the aforementioned electromagnet isgiven by the decoding of that bit interval which is distant from thestart interval by the said definite selected interval of time. Thedecoding of the bit interval which gives the reading command thus varieswith the telegraphic speed, since an alteration of the latter results inan alteration of the interval of time between the start interval DST andthe individual bit intervals. Consequently, the decodings of the bitintervals Dl D8 enter a selection network 33, to which six differentsignals generated by the speed change switch 22 likewise have access.With each speed is associated a corresponding decoding of the bitintervals Dl D8, so that from the selection network 33, a signal AVLemerges, at a moment which varies according to the speed, and enters thegate 34 which is enabled by the signal VL, and from which emerges asignal AVLA which energizes the reading command electromagnet of thereader LA. After the fixed time of the reader LA itself, the outputmicroswitches of the latter are placed according to the character whichhas been read and is available at the path 2, and thus, after the gate11 is actuated by the decoding of the start bit DST, is available at theregister M. The character can thus be extracted in successive bits, inview of the aforementioned synchronization between the operation of thereader and the serialization.

FIG. 3 gives the time diagram of the reading command of the reader LA,in the example based on two telegraphic speeds of 50 and baud. Thediagram D100 in FIG. 3 shows the bit intervals in the case oftelegraphic transmission at I00 baud. it is noted that the characterread by the reader LA at an instant within the DST start interval is tobe available in the register M. The character remains available at theoutput microswitches of the reader LA for an interval of timerepresented by a signal DIS. The fixed time of the reader LA itself,lasting up to the moment at which the character read is to be availableto the output microswitches of the reader, from the moment when thereading command is given, is identified by the letter As may be seenfrom the three upper diagrams, to ensure that the character read by thereader LA will be available at the register M at a moment within theinterval DST, the reading command AVLA must be given by decoding the bitinterval D5. With reference to the three lower diagrams of FIG. 3 whichrelate to the case in which telegraphic transmission is effected at 50baud, the reading command AVLA must be given by decoding the bitinterval D8. The selection of the bit interval to be decoded is made byselection network 33 under control of the signal a to f selected byswitch 22.

The automatic reply device RA is likewise a device with a step-by-stepfeed. It is started up by a key SRA present in the machine or by asignal RlC emanating from the function decoding assembly present in thereceiving unit. The aforementioned signals generate a VR signal which ispresent con- 4 tinuously. In this case likewise, therefore, the timingdevice continues in operation, supplying trains of lO-bit intervals. Thecharacters read by the device RA, therefore, must at each start beavailable at the register M. Unlike the tape reader, the automatic replydevice does not merely act on the output switches for a short space oftime, and the latter remain in action until the new positioningoperation, so that any decoding signal of the bit intervals DST, Dl D8,can be taken for the purpose of subsequently giving the command for feedand reading of the aforementioned device RA. In particular, the signalDST, after passage through gate 35 actuated by the signal VR supplies,on each character cycle, the feed and reading order to the automaticreply device RA, energizing the electromagnet present in the apparatusand provided for this purpose.

CHANGE OF SPEED (TRANSMITTING UNIT) The speed change system provided forthe transmission according to the invention enables the telegraphicspeed of the messages to be varied without modifying the speed of themechanical component of the machine, such as the keyboard, the tapereader and the automatic reply device.

The speed with which the keys are operated must be less than the minimumpossible telegraphic speed, in order to ensure that the character keyedin is passed to line before the subsequent character is keyed in andthat no characters will thus be superimposed in the register M. Thespeed of the reader and of the automatic reply device, on the otherhand, need not be limited, because the two devices, after a characterhas been supplied, will come to a stop and will not restart until theorder is given by the timing device, at the end of the serialization ofthe preceding character.

With reference to FIG. 1, the change of speed is obtained by actingdirectly on the timing device which determines the out put sequence ofthe bits.

In particular, an oscillator 23, which is started up when the machine isset in operation, generates a square wave of a certain frequency whichfeeds certain stages of a frequency divider 24, of a known type. Thedifferent outputs of the stages of the aforementioned-divider 24 are intheir turn conveyed to a selection network 25 which also receive the sixsignals a, b, c, d, e and f, generated by switches constituting thespeed selection switch 22, which is provided on the outside of themachine and which can be used by the operator for varying the speed. Inparticular, let us suppose that the positions of the selection switch onthe outside of the apparatus are six in number, corresponding to the sixdifferent telegraphic speeds 50, I00, lSO, 200, 300 and 400 baud. Witheach different telegraphic speed is associated a switch which generatesa different one of the signals a to f. The selection network 25, whoseinput includes the signals a to f emanating from the six switches andalso the outputs of the stages of the frequency divider 24, serves toselect, in accordance with the signal emanating from the selectionswitch 22, the frequencycorresponding to the position of the saidselection switch, among the six different frequencies obtained by thedivision of the aforementioned divider. The selection network thereforeemits the frequency signal equal to that selected with the selectionswitch 22 and, if the gate 13 is actuated by one of the track signalsVT, VL and 'VR emanating from the input devices TA, LA and RA,respectively, the frequency signal enters a counter 26 which counts intens. From the counter 26 the signals enter a decoding circuit 27 whichsupplies the interval DST, which is the initial starting interval, thecharacter intervals D1 D8 and the stop interval DSP. The decoding of theinternal DSP prevents the signal VT from being emitted by the keyboardTA and thus likewise blocks the counter 26, which will once againinitiate the counting operation when the subsequent character is keyedin, The signals representing the start and stop intervals go direct tothe line, while the signals D1 D8 actuate the gates 14 21, respectively,for the emission in sequence, of the bits stored in the flip-flops Ml M8of the register M. The register M is fed with the character emanatingfrom the keyboard or from the tape reader or from the automatic replydevice, when enabled by the signal K having the desired frequency andemanating from the selection network 25 and from the gate 13. Since thetelegraphic speed is thus modified solely by action at the electroniclevel, all the mechanical components of the machine maintain the speedfor which they are designed and are, therefore, not subjected to anyunforeseen fatigue or undesirable irregularity.

DESCRIPTION OF RECEIVING UNIT The receiving unit receives the codedcharacters emanating from the line and expressing alphanumerical datawhich, in particular, can be supplied to a printing unit and a tapepunch, or data expressing function commands which are to be carried outby the unit. The data consisting of 7+1 bits preceded by a start bit andfollowed by a stop bit arrive from the transmission line at a ratedetermined by the transmission speed selected. The bits enter in seriesinto a shift register I of a type already known in itself and consistingof bistable flip-flops. A timing device serves to shift the enteringbits, according to the speed selected by the operator by means of aswitch 42 and being naturally the same speed as that of the bits whicharrive from the line. A signal PR1 emerging from the timing devicetherefore causes a shift, into the register I, of the entire characterpreceded and followed by the start bit and the stop bit, respectively.When the stop bit is present in the flip-flop I1, i.e., when the entirecharacter is stored in the register I, the start bit of the subsequentcharacter arrives from the line, so that, since the interval between theeighth bit of the first character and the subsequent start bit of thesecond character is too short by comparison with the time required forthe form, such as interlining,

preparation of the first character present in the register I, the saidcharacter is stored in another register ll, after the actuation ofa gate53. Actuation of that gate is caused by the signal S, effected by adecoding circuit 54, which senses the presence of the start bit in theflip-flop l 10, thereby confirming the complete introduction of thefirst character into the register I. The first character, emanating fromthe line L, thus passes to the register II, where it is present for thespace of time corresponding to one character, i.e., until the subsequentcharacter, emanating from the line, has been completely introduced intothe register I.

On the arrival of the first character emanating from the line, the motor61 of the machine is started up and sets in operation a timing device62, of which the timing cycle is, for example, shorter than the intervalof a character. Within this timing cycle, all the functions of themachine are actuated. The timing device 62, in particular, consists of adisc of insulating material, which rotates synchronously with the motorshaft and of which the periphery bears a plate of magnetic material, bywhich on each rotation, a magnetic detector, which scans the peripheryof the disc, supplies a signal On each new character, i.e., if thesignal S, which represents the decoding of the flipflop I 10 of theregister I, confirming the presence of the start bit in theaforementioned flip-flop, opens a gate 55, a signal Z emerges from thisgate and, by actuating agate 56, enables the character stored in theregister II to pass to a third register Ill. The character present inthe register III can be an item which is to be printed and punched or afunction command which can be punched and not printed. In either case,as soon as a character is present in the register III, eightelectromagnets 63, corresponding to the respective bits of thecharacter, are energized or deenergized, according to the code Inparticular, the electromagnets can position code bars of a printingdevice of the kind described in the specification of our US. Pat. No.3,356,198. At the same time, the character present in the register IIIis decoded by a decoding block 64 for the function codes. Now if thecharacter is to be printed, the function decoding block energizes anelectromagnet 65, which controls a printer striking bar, so that thecharacter corresponding to the arrangement already selected for the codebars is printed and the function decoding block 64 at the same timeenergizes an electromagnet 66 which causes the carriage to be fedforward by one step. If the character decoded by the decoding block 64represents a function which the machine is to perthe return of thecarriage, a return movement by one step, then the striking bar of theprinting unit remains inoperative, while the appropriate one of threeelectromagnets 67, 68 and 69, which actuate the respective decodedfunctions, is energized.

The character present in the register III, furthermore, excites eightelectromagnets 70, which position the corresponding bars of a punch,while the function decoding block 64 supplies, for each character, acommand signal for the punching, which energizes an electromagnet 71. Ifthe character present in the register III is not to be punched, theelectromagnet 71 is not energized, and the electromagnets 63 and alsothe electromagnets 70 remain ineffective.

If, on the other hand, the character present in the register IIIrepresents a request for the address of the receiving unit, the functiondecoding block 64 emits a signal RIC which sets in operation theautomatic reply device RA, thus leaving the bars of the printing deviceand the bars of the punching device inoperative.

CHANGE OF SPEED (RECEIVING UNIT) As already stated, the bits of thecharacters received occur at a rate which is determined by thetransmission speed, which must be the same as the shifting speed of thecharacter in the register I. The transmission speed is decided by thetwo operators stationed at the communication units at the ends of theline. The operator responsible for the receiving unit uses his speedchange switch 42 which, in particular, selects one of the speeds 50,100, 150, 200, 300, and 400 baud. With reference to FIG. 2, with eachdifferent position of the changeover switch, i.e., with each differenttelegraphic speed, is associated a switch which generates a differentsignal. The signals g, h, i, l, m, and n, emanating from the sixswitches. enter a selection network 43.

The selection network 43 also receives six different signals with sixdifferent frequencies corresponding to the six different positions ofthe speed change switch 42. Thus an oscillator 44 generates a squarewave ofa certain frequency, which feeds a several stage frequencydivider 45, known in itself and producing the respective signalsrepresenting the six different frequencies required. The purpose of theselection network 43 is therefore to select in accordance with each ofthe signals g, h, i, I, m, and n, emanating from the speed changeswitch, the frequency corresponding to the position of the switch, fromamong the six frequencies obtained by the division by the aforementioneddivider 45.

From the selection network 43 the signal PR1, with the same frequency asthat in which the bits of the character received occur in succession,effects the "shift," in the register lofthe bits ofthe receivedcharacter.

The speed variation is thus effected at an electronic level, at theinput of the control of the machine without acting on the mechanicalcomponents of the apparatus, such as the printing device and thepunching device, which thus can continue to operate at the same speed atall times. it will then be understood that this same speed (also in thecase of the transmitting unit) refers to the speed with which amechanical cycle is executed, not the rate with which the cycles followone another.

it will further be understood that many modifications can be made in theembodiment of the invention illustrated herein, without departure fromthe scope of the invention. Accordingly, the invention is not to beconsidered limited to illustrated embodiment, but rather only by thescope of the appended claims.

What is claimed is:

1. in a telegraphic system including a transmission line operating at atransmission speed, a transmitting apparatus including a teleprinterunit conditionable for processing code combinations cyclically atpredetermined speed, a keyboard for entering a character comprising bitscomprising one ofsaid combinations, a register connected to saidkeyboard for temporarily storing the bits of the character codecombination being processed, and a timing device for rhythmicallycontrolling the connection of said line with said register, said timingdevice including an oscillator for generating timing pulses at apredetermined frequency, and a transmission speed adapter comprising:

a frequency divider for dividing the output of said oscillator togenerate timing pulses corresponding to a plurality of operatingfrequencies, said transmission speed corresponding to one of saidoperating frequencies,

a frequency selection network receiving the output pulses of saidfrequency divider and providing timing pulses corresponding to saidoperating frequency,

a manually operated switch coupled to said selection network to selectthe operating frequency of said network and including a plurality ofoutputs, each of said outputs associated with one ofsaid operatingfrequencies,

counter means connected to said frequency selection network forreceiving said timing pulses,

decoder means coupled to said counter means for generating signals totime the individual bits of the character of said code combination andfor generating a cyclic signal, and

gate means controlled jointly by the timing pulses of said selectedoperating frequency and by said cyclic signal to disconnect saidregister from said keyboard and to disable said counter means upontransmitting the character bits of said code combination on saidtransmission line. 2. ln :1 telegraphic system including a transmissionline operating at a transmission speed, a transmitting apparatusincluding a teleprinter unit conditionable for processing codecombinations cyclically at predetermined speed, an input deviceoperating to supply characters in a step-by-step sequence, each of saidcharacters comprising bits comprising one of said code combinations, aregister connected to said input device for temporarily storing the bitsof the character code combination being processed and a timing devicefor rhythmically controlling the connection of said line with saidregister, said timing device including an oscillator for generatingtiming pulses at a predetermined frequency, and a transmission speedadapter comprising:

a frequency divider for dividing the output of said oscillator togenerate timing pulses corresponding to a plurality of operatingfrequencies, said transmission speed corresponding to one ofsaidoperating frequencies,

a manually operated switch to select the operating frequency of saidnetwork including a plurality of outputs, each of said outputsassociated with one of said operating frequencies,

a frequency selection network receiving the output pulses of saidfrequency divider and responsive to said switch to provide timing pulsescorresponding to said operating frequency,

counter means connected to said frequency selection network forreceiving said timing pulses,

decoder means coupled to said counter means for generating signals totime the individual bits of the character of said code combination andfor generating a cyclic signal,

gate means controlled jointly by the timing pulses of said selectedoperating frequency and by said cyclic signal to disconnect saidregister from said input device and to disable said counter means upontransmitting the bits of character information comprising said codecombination of said line,

supplying means for supplying command signals to said input device,

means for placing the bits ofa character in the register for arelatively short interval occurring a fixed time after the commandsignal has been furnished to the input device,

a plurality of gates connected between the register and the line tofurnish the bits to the line in succession when the respective gates areactuated, and

means for providing the timing signals from the decoder sequentially tosaid gates, said supplying means including a second selection networkcontrolled by said manually operated switch for selecting different onesof the decoder signals to constitute said command signal.

3. The system of claim 1 wherein said teleprinter unit comprises areceiving unit including a shift register receiving the timing pulses asshift pulses for received character bits,

said decoder means including means for generating a second cyclic signalwhen all the bits of a character are stored in the shift register,

second gate means conditionable by said second cyclic signal forconnecting said first additional register to said shift register, and

a second additional register controlled by a third cyclic signal havinga frequency higher than the frequency of said second cyclic signalcorresponding to a maximum transmission speed for causing the bitsstored in said first additional register to be transferred to saidsecond additional register whereby the bits stored in said firstadditional register are transferred to said second additional registerbefore all bits of the next character have reached the said second shiftregister.

1. In a telegraphic system including a transmission line operating at atransmission speed, a transmitting apparatus including a teleprinterunit conditionable for processing code combinations cyclically atpredetermined speed, a keyboard for entering a character comprising bitscomprising one of said combinations, a register connected to saidkeyboard for temporarily storing the bits of the character codecombination being processed, and a timing device for rhythmicallycontrolling the connection of said line with said register, said timingdevice including an oscillator for generating timing pulses at apredetermined frequency, and a transmission speed adapter comprising: afrequency divider for dividing the output of said oscillator to generatetiming pulses corresponding to a plurality of operating frequencies,said transmission speed corresponding to one of said operatingfrequencies, a frequency selection network receiving the output pulsesof said frequency divider and providing timing pulses corresponding tosaid operating frequency, a manually operated switch coupled to saidselection network to select the operating frequency of said network andincluding a plurality of outputs, each of said outputs associated withone of said operating frequencies, counter means connected to saidfrequency selection network for receiving said timing pulses, decodermeans coupled to said counter means for generating signals to time theindividual bits of the character of said code combination and forgenerating a cyclic signal, and gate means controlled jointly by thetiming pulses of said selected operating frequency and by said cyclicsignal to disconnect said register from said keyboard and to disablesaid counter means upon transmitting the character bits of said codecombination on said transmission line.
 2. In a telegraphic systemincluding a transmission line operating at a transmission speed, atransmitting apparatus including a teleprinter unit conditionable forprocessing code combinations cyclically at predetermined speed, an inputdevice operating to supply characters in a step-by-step sequence, eachof said characters comprising bits comprising one of said codecombinations, a register connected to said input device for temporarilystoring the bits of the character code combination being processed and atiming device for rhythmically controlling the connection of said linewith said register, said timing device including an oscillator forgenerating timing pulses at a predetermined frequency, and atransmission speed adapter comprising: a frequency divider for dividingthe output of said oscillator to generate timing pulses corresponding toa plurality of operating frequencies, said transmission speedcorresponding to one of said operating frequencies, a manually operatedswitch to select the operating frequency of said network including aplurality of outputs, each of said outputs associated with one of saidoperating frequencies, a frequency selection network receiving theoutput pulses of said frequency divider and resPonsive to said switch toprovide timing pulses corresponding to said operating frequency, countermeans connected to said frequency selection network for receiving saidtiming pulses, decoder means coupled to said counter means forgenerating signals to time the individual bits of the character of saidcode combination and for generating a cyclic signal, gate meanscontrolled jointly by the timing pulses of said selected operatingfrequency and by said cyclic signal to disconnect said register fromsaid input device and to disable said counter means upon transmittingthe bits of character information comprising said code combination ofsaid line, supplying means for supplying command signals to said inputdevice, means for placing the bits of a character in the register for arelatively short interval occurring a fixed time after the commandsignal has been furnished to the input device, a plurality of gatesconnected between the register and the line to furnish the bits to theline in succession when the respective gates are actuated, and means forproviding the timing signals from the decoder sequentially to saidgates, said supplying means including a second selection networkcontrolled by said manually operated switch for selecting different onesof the decoder signals to constitute said command signal.
 3. The systemof claim 1 wherein said teleprinter unit comprises a receiving unitincluding a shift register receiving the timing pulses as shift pulsesfor received character bits, said decoder means including means forgenerating a second cyclic signal when all the bits of a character arestored in the shift register, second gate means conditionable by saidsecond cyclic signal for connecting said first additional register tosaid shift register, and a second additional register controlled by athird cyclic signal having a frequency higher than the frequency of saidsecond cyclic signal corresponding to a maximum transmission speed forcausing the bits stored in said first additional register to betransferred to said second additional register whereby the bits storedin said first additional register are transferred to said secondadditional register before all bits of the next character have reachedthe said second shift register.